Bacterial infections continue to remain one of the major causes contributing towards human diseases. One of the key challenges in treatment of bacterial infections is the ability of bacteria to develop resistance to one or more antibacterial agents over time. Examples of such bacteria that have developed resistance to typical antibacterial agents include: Penicillin-resistant Streptococcus pneumoniae, Vancomycin-resistant Enterococci, and Methicillin-resistant Staphylococcus aureus. The problem of emerging drug-resistance in bacteria is often tackled by switching to newer antibacterial agents, which can be more expensive and sometimes more toxic. Additionally, this may not be a permanent solution as the bacteria often develop resistance to the newer antibacterial agents as well in due course. In general, bacteria are particularly efficient in developing resistance, because of their ability to multiply very rapidly and pass on the resistance genes as they replicate.
The persistent exposure of bacterial strains to a multitude of beta-lactam antibacterial agents has led to overproduction and mutation of beta-lactamases. These new extended spectrum beta-lactamases (ESBL) are capable of hydrolyzing penicillins, cephalosporins, monobactams and even carbapenems. Such a wide spread resistance to many of the existing beta-lactam antibacterial agents, either used alone or in combination with other agents, is posing challenges in treating serious bacterial infections.
Therefore, there is a need for development of newer ways to treat infections that are becoming resistant to known therapies and methods. Surprisingly, it has been found that compositions comprising a carbapenem antibacterial agent and certain nitrogen containing bicyclic compounds (disclosed in PCT/IB2012/054290) exhibit unexpectedly synergistic antibacterial activity, even against highly resistant bacterial strains.